There are 2 possible scenarios that can cause this, it's hard to tell which one you are having if we don't see the SQL file you are trying to import.
Maybe your default engine isn't the same on both servers.
If you are loading data in a MyISAM table on your localhost and a InnoDB table on Real CMS this could cause the issue because the maximum prefix is 767 bytes long for InnoDB and 1000 bytes for MyISAM. So if you have a key with a prefix of, lets say, 800 bytes it would load fine on your localhost but not in Real CMS.
It could also be caused by a different server configuration. The max key length for a MyISAM table can be controlled by the
innodb_large_prefix system variable.
Please see the documentation for CREATE INDEX which states:
Prefix support and lengths of prefixes (where supported) are storage
engine dependent. For example, a prefix can be up to 767 bytes long
for InnoDB tables or 3072 bytes if the innodb_large_prefix option is
enabled. For MyISAM tables, the prefix limit is 1000 bytes. The NDB
storage engine does not support prefixes